Devices such as natural gas compressors, air compressors, steam turbines, and gas turbines, include various internal components, such as vanes, stators, blades, diffusers, housings, and combustors though which quantities of air, natural gas, steam, or combusted gas flow. It is important to the proper operation of these devices that these internal components modify the internal flow in the correct way. These modifications include changing the average properties of the flowing medium (such as pressure, temperature, density, velocity, etc.) and/or the profiles and gradients of these properties.
These internal components are designed to change the properties of the flowing medium within the context of the device, i.e., change the properties in respect to internal devices either upstream or downstream of the particular component. For example, the first stage turbine vane of a gas turbine engine receives combusted air from a combustor and provides the combusted air to turbine blades located downstream. Even though these internal components are designed to interact with upstream and downstream components during operation of the device, it is often not possible or too difficult and expensive to measure characteristics of the internal component during operation of the device. Therefore, it is important to be able to measure characteristics of the device prior to assembling the component within the device. For example, vanes of gas turbine engine are often flow tested during the manufacturing process and prior to assembly. This manufacturing phase flow test is often used to determine whether or not the particular internal component will be assembled and tested within the larger overall device.
These manufacturing airflow tests sometimes produce results that are not representative of the operation of the particular internal component within the assembled device. In particular, the inferred characteristic of the component (such as the equivalent flow area of the gas turbine vane) is affected by uncontrolled aspects of the manufacturing tests. These uncontrolled aspects cause the value of the inferred characteristic to be erratic or wrong.
What is needed is an improvement in airflow testing that improves the accuracy and repeatability of the airflow tests. The present invention does this in a novel and nonobvious manner.